Reduction gear and geared motor

Abstract

A reduction gear configured to decelerate and output rotation of a motor by two-stage planetary gear mechanisms disposed side by side in an axial direction includes: a case made of resin, the case being formed into a cylindrical shape in which the two-stage planetary gear mechanisms are incorporated, and having at least one of a lid portion and a bottom portion provided at each of both axial ends; and a reinforcing component that is formed of a material having a Young's modulus higher than a Young's modulus of a material of the case. The reinforcing component extends along at least a part of an inner peripheral surface in an axial central portion of the case.

What is claimed is: 
     
       1. A reduction gear configured to decelerate and output rotation of a motor by two-stage planetary gear mechanisms disposed side by side in an axial direction, the reduction gear comprising:
 a case made of resin, the case being formed into a cylindrical shape in which the two-stage planetary gear mechanisms are incorporated, and having at least one of a lid portion and a bottom portion provided at each of both axial ends; and 
 a reinforcing component that is formed of a material having a Young's modulus higher than a Young's modulus of a material of the case and extends along at least a part of an inner peripheral surface in an axial central portion of the case. 
 
     
     
       2. The reduction gear according to  claim 1 , wherein the reinforcing component has a ring shape extending over an entire circumference of the case in the axial central portion of the case. 
     
     
       3. The reduction gear according to  claim 2 , wherein the reinforcing component is located between pinion gears of the two-stage planetary gear mechanisms. 
     
     
       4. The reduction gear according to  claim 2 ,
 wherein the inner peripheral surface of the case includes a small-diameter inner peripheral surface and a large-diameter inner peripheral surface having different inner diameters from each other in the axial direction, and a tapered surface connecting the small-diameter inner peripheral surface and the large-diameter inner peripheral surface and inclined in the axial direction, and 
 the reinforcing component is press-fitted into the case and disposed at a position in contact with a boundary line between the large-diameter inner peripheral surface and the tapered surface. 
 
     
     
       5. The reduction gear according to  claim 2 , wherein the case has a bottomed cylindrical shape having the bottom portion at one axial end and the lid portion at another axial end, and is attached to the motor in a direction in which the bottom portion is located on a motor side. 
     
     
       6. The reduction gear according to  claim 5 , wherein the lid portion is press-fitted into an opening at the other axial end of the case. 
     
     
       7. The reduction gear according to  claim 1 , wherein the reinforcing component is located between pinion gears of the two-stage planetary gear mechanisms. 
     
     
       8. The reduction gear according to  claim 7 ,
 wherein the inner peripheral surface of the case includes a small-diameter inner peripheral surface and a large-diameter inner peripheral surface having different inner diameters from each other in the axial direction, and a tapered surface connecting the small-diameter inner peripheral surface and the large-diameter inner peripheral surface and inclined in the axial direction, and 
 the reinforcing component is press-fitted into the case and disposed at a position in contact with a boundary line between the large-diameter inner peripheral surface and the tapered surface. 
 
     
     
       9. The reduction gear according to  claim 7 , wherein the case has a bottomed cylindrical shape having the bottom portion at one axial end and the lid portion at another axial end, and is attached to the motor in a direction in which the bottom portion is located on a motor side. 
     
     
       10. The reduction gear according to  claim 9 , wherein the lid portion is press-fitted into an opening at the other axial end of the case. 
     
     
       11. The reduction gear according to  claim 1 ,
 wherein the inner peripheral surface of the case includes a small-diameter inner peripheral surface and a large-diameter inner peripheral surface having different inner diameters from each other in the axial direction, and a tapered surface connecting the small-diameter inner peripheral surface and the large-diameter inner peripheral surface and inclined in the axial direction, and 
 the reinforcing component is press-fitted into the case and disposed at a position in contact with a boundary line between the large-diameter inner peripheral surface and the tapered surface. 
 
     
     
       12. The reduction gear according to  claim 11 , wherein the case has a bottomed cylindrical shape having the bottom portion at one axial end and the lid portion at another axial end, and is attached to the motor in a direction in which the bottom portion is located on a motor side. 
     
     
       13. The reduction gear according to  claim 12 , wherein the lid portion is press-fitted into an opening at the other axial end of the case. 
     
     
       14. The reduction gear according to  claim 1 , wherein the case has a bottomed cylindrical shape having the bottom portion at one axial end and the lid portion at another axial end, and is attached to the motor in a direction in which the bottom portion is located on a motor side. 
     
     
       15. The reduction gear according to  claim 14 , wherein the lid portion is press-fitted into an opening at the other axial end of the case. 
     
     
       16. A geared motor comprising:
 a reduction gear configured to decelerate and output rotation of a motor by two-stage planetary gear mechanisms disposed side by side in an axial direction, the reduction gear comprising: 
 a case made of resin, the case being formed into a cylindrical shape in which the two-stage planetary gear mechanisms are incorporated, and having at least one of a lid portion and a bottom portion provided at each of both axial ends; and 
 a reinforcing component that is formed of a material having a Young's modulus higher than a Young's modulus of a material of the case and extends along at least a part of an inner peripheral surface in an axial central portion of the case; and 
 the motor having a shaft integrally rotating with a sun gear of the planetary gear mechanism in a first stage of the reduction gear.